byte[] captchaChallengeAsJpeg = null; // the output stream to render the captcha image as jpeg intoByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream(); try { // get the session id that will identify the generated captcha. //the same id must be used to validate the response, the session id is a good candidate!String captchaId = httpServletRequest.getSession().getId(); // call the ImageCaptchaService getChallenge methodBufferedImage challenge = CaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId, httpServletRequest.getLocale());

In your singleton (CaptchaServiceSingleton in your case), you define a custom ImageCaptchaEngine of some sort. We extend ListImagecaptchaEngine and provide our own settings. See the API for more options.

Note this isn't the most secure, but is the best our users are able to manage.

Once you have your engine, you plug it into your Engine in a static initialiser:

I tried the above hint. But setCaptchaEngine is not a method of DefaultManageableImageCaptchaService.
Is there any other way to change the font properties etc without using spring config
Can someone help with it.
Appreciate your help!!